Abstract: Hsp-Tat fusion protein was expressed in BL21 (DE3) E.coli cells and purified by using affinity chromatography method. The size and morphology of Hsp-Tat nanoparticles were analyzed by dynamic light scattering and transmission electron microscopy. MTT analysis and live/dead cell staining were used to study the biocompatibility of Hsp-Tat nanoparticles. The siRNA complex properties of Hsp-Tat nanoparticles were detected by gel retardation assay. The siRNA transfection activity was studied by laser confocal fluorescence microscopy imaging. The experimental results show that Hsp-Tat fusion protein with high purity is obtained by affinity chromatography. Hsp-Tat nanoparticles can self-assemble into  spherical nanostructures with a mean diameter of 40.2 nm. The protein nanoparticles show good biocompatibility on HEK\|293T cells. The  complexes formed by Hsp-Tat NP and siRNA can prevent the migration of siRNA in agarose gel. Hsp-Tat nanoparticles can  transport Cy3-siRNA into HEK-293T cells, and can  be used as  a  safe and efficient non-viral nucleic acid delivery vector.

Key words: heat shock protein; , cell-penetrating peptide; , protein nanoparticle; , siRNA delivery; , cell transfection